"We found the site with the aid of aerial photographs," expedition leader Ivan Šprajc said in a statement, "but were able to identify it with Lagunita only after we saw the façade and the monuments and compared them with Von Euw’s drawings, which the renowned Maya expert Karl Herbert Mayer made available for me."

The two sites are located in Mexico's Yucatan peninsula near the Calakmul Biosphere Reserve.

According to the academy, one of the two sites was first discovered in the 1970s by American archaeologist Eric Von Euw. While Euw documented his discovery of the site through paintings of several stone monuments and "an extraordinary façade with an entrance representing open jaws of the earth monster," he never published his findings.

The archeologists named that site Lagunita and the other site was called Tamchén (Deep Well) because of the large number of "chultunes" (wells, or water holes) found in the area.

His drawings, which have resided at Harvard University's Peabody Museum of Archaeology and Ethnology, have been used by archeologists attempting to relocate the site, but all efforts have failed because they did not specifically identify the location of the ruins.

"The information about Lagunita were vague and totally useless," Sprajc told Discovery News.

"In the jungle you can be as little as 600 feet from a large site and do not even suspect it might be there; small mounds are all over the place, but they give you no idea about where an urban center might be," he added.

Sprajc and his team were exploring the area near another Mayan city that was found in 2013 by a Slovenian archaeologist.

Those ruins were complete with signs of pyramids and remnants of palace buildings. The site, Sprajc told the Los Angeles Times, represented a "total gap in the archeological map of the Maya area."

In June 2014, the southern part of the Calakmul Biosphere Reserve, where Sprajc's team has been most actively surveying in recent years, was added to the United Nations Organization for Education, Science and Culture's World Heritage list as a mixed natural and cultural property, according to Past Horizons, a website dedicated to archeological adventures.

Deep in the southeastern part of the Mexican state of Campeche, the remnants of two ancient Mayan cities have been unearthed by archeologists, reports the Research Centre of the Slovenian Academy of Arts and Sciences, which funded the expedition.